486 A MANUAL OF BACTERIOLOGY 



obtain a saturated solution ; then pour off and add a further 

 quantity of alcohol -glycerin solution, and repeat the trituration ; 

 about 100 c.c. stain can be made from the quantity given. 



The solution, when filtered, should be kept in a well-stoppered 

 bottle (and if a completely saturated solution has been obtained, 

 add 10 per cent, more alcohol-glycerin mixture). The stain may 

 be purchased ready for use. 



Tissues to be examined should be fixed in Miiller's fluid con- 

 taining 10 per cent, of formalin, but on no account should 10 per 

 cent, formalin alone be used. 



Paraffin sections (after xylol, alcohol and distilled water) are 

 stained for about five minutes with the stain made up by mixing 

 one part of distilled water with two parts of the glycerin-alcohol 

 stain solution. Sometimes in staining such organisms as glanders 

 ten minutes may be necessary, especially if insufficient stain is in 

 solution and the room temperature is low. Rinse in distilled 

 water. 



Fix for half to one minute in Unna's glycerin-ether mixture 

 2 per cent, in distilled water. Rinse in distilled water. 



Differentiate and dehydrate in absolute alcohol. Should there 

 be much precipitate, this can easily be removed by a few drops 

 of methyl alcohol, or better by a mixture of equal parts of absolute 

 alcohol and xylol. Pass through xylol and mount. 



Various elements stain different colours, viz. chromatin of nuclei, 

 purple red ; mucoid and colloid degenerations, bright orange red ; 

 fetal cartilage, orange red ; fibrous tissue, blue-green ; erythrocytes, 

 light grass -green. Micro-organisms stain bright red and stand out 

 in marked contrast to the green connective tissue containing 

 them. 



Animal parasites, e.g. amcebaa, also stain well. The stain has 

 the advantage of leaving all the tissues sharply differentiated. 



Allusion may here be made to the Mycetozoa (Myxomycetes). 

 These are masses of protoplasm resembling huge amoebae, which 

 are found on decaying vegetable matter. By some they are regarded 

 as vegetable, by others as animal, in nature, and belonging to the 

 Amoebae of the Sarkodina. 1 Some important plant diseases, such 

 as the " finger-and-toe " of cabbage roots, are due to their activity. 

 The finger-and-toe disease is due to an amoaboid parasite (Plasmo- 

 diophora brassicce, by some included among the Amcebce), the cycle 

 of which begins with spores from which small flagellulae are set 

 free. Similar organisms have been supposed to be present in cancer. 



1 See Lankester's Treatise en Zoology, Pt. 1, First Fascicle, p. 37. 



